1. Technical Field
The present invention relates to a switch over device, and more particularly, relates to a device for switching over a double construction.
2. Related Art
Conventional highly reliable communication systems typically contain standby modules which operate in parallel to active modules and a specific processor which controls switching between the active or standby modules for communication protection purposes. Exemplary switching arrangements are disclosed in U.S. Pat. No. 4,455,601 for Cross Checking Among Service Processors In A Multiprocessor System issued to Griscom et al., U.S. Pat. No. 4,654,784 for Circuit Arrangement For Routing Signals Between A Master-Slave Pair Of Controlling Processors And Several Master-Slave Pairs Of Controlled Processing Units issued to Campanini, U.S. Pat. No. 4,710,952 for Distributed Control Type Electronic Switching System issued to Kobayashi, U.S. Pat. No. 5,251,299 for System For Switching Between Processors In A Multiprocessor System issued to Masuda et al., U.S. Pat. No. 5,408,462 for Protection Switching Apparatus And Method issued to Opoczynski, and U.S. Pat. No. 5,570,345 for Protection Switching System With Single Line Control issued to Kaprielian et al.
Generally, an active/standby mode is determined by the specific processor for controlling a double construction which is a double board supporting communication modules. Upon detecting a change of the status of the double construction, the processor switches over the active/stand-by status. Then, the active module is activated and the standby module is deactivated. Such operations are controlled by the processor. Therefore, the software for the processor may become complicated. Moreover, since the processor controls a switchover signal through bus lines, a control process may become complicated, and may not be diversified.
While the conventional switching systems such as disclosed in Griscom et al. '601, Campanini '784, Masuda '299, Opoczynski '462, and Kaprielian et al. '345 are technically noteworthy, I have observed that these switching systems may not be suitable for switching over the double module because of their structural problems. Accordingly, I believe that switchover device can still be improved.